Quantitative source apportionment of surface ozone in Liaoning Province, China, under the Asian summer monsoon background

Abstract

At present, few quantitative study has been carried out on the proportion of local generation and long range transport of ozone in Liaoning, which is the key to reveal regional ozone pollution. Using the Ozone Source Apportionment Technology in the CAMx model, surface ozone concentrations in Liaoning Province, China, were simulated during the warm season of 2023. The contributions of 23 source regions, five industrial sectors, and two chemical precursors to ozone concentrations in 14 cities in Liaoning were determined under the Asian summer monsoon (ASM) background. The major components were lowest in May and increased from June to August, reflecting a significant increase in the northward transport of ozone and its precursors from upstream regions (north and east China) with the onset of the ASM. The contribution of surrounding provinces to Liaoning's ozone embodied the principle of "proximity and directness" - the more direct the transport direction of the ASM and the closer the source province to the receptor city, the greater the contribution from source to receptor. Under the ASM background, most ozone was transported from upwind to downwind cities within Liaoning (e.g., Dalian contributed 1.44 % to Anshan, Dandong contributed 1.76 % to Benxi), indicating that the prevailing southwest wind transported ozone and its precursors from upstream cities, contributing to the ozone concentrations in downstream cities. The results may provide reference for regional ozone pollution control.